Get array from PHP using $.post Jquery

<html>
<head>
<script>
function getphp(hora) {
    $.post("page.php",
    {'value': 2, 'plus': 4},
    function(data,status){
        alert("value = "+data[0]+"+4="+data[1]+" - "+status);//data.length
    }, "json");
}
</script>
</head>
</html>

//page.php

<?php
$val1= $_POST['value'];
$val2 = $_POST['plus'];
$re = array();
$re[0] = $val1;
$re[1] = $val1+$val2;
echo json_encode($re);
?>